2010 Two Coin Proof Year Set, 150th Anniversary of the Burke and Wills Expedition. On 20th August 1860, nineteen men set out from Melbourne to traverse Australiafrom south to north, a feat never achieved before. The 20c coin illustrates Burke and Wills setting out and the $1 coin illustrates King, the sole survivor of the expedition, sitting under the 'Dig Tree'. On both designs, the camel stracks represent the expedition route and the footprints are symbolic of the assistance of the Aboriginal people. Mintage , No more than 25,000. $1 Metal Aluminium Bronze, Weight 9.0 grams, Diameter 25.00 mm, Finish Proof, 20c Metal Cupro Nickel, Weight 11.3 grams, Diameter 28.52 mm, Finish Proof. Please contact Adelaide Exchange Jewellers to find out more on this item.